Peel the sweet potato and parsnip and shred using a grater or food processor. Wrap the shredded sweet potato and parsnip in a few paper towels and squeeze to remove excess liquid.

In a large bowl, mix the sweet potato and parsnip with the scallions, eggs, flour, salt and pepper.

Heat a large iron skillet over medium-high heat. Add enough vegetable oil to cover the bottom and come up the sides at least a quarter of an inch. When the oil is hot, scoop about 1/4 cup of latke mixture into the pan and slightly flatten. Repeat until the pan is full but not crowded. Brown the latkes on each side 3-4 minutes.

Set aside on a plate lined with paper towels when done. While the latkes are cooking, stir together the sour cream and minced apple.